In 1953, Gonzalez ran again and this time won election to the San Antonio City Council, serving as mayor pro-tempore for part of his first term. His tenure on the council was a continuation of his efforts in reform. He spoke out against segregation of public facilities, opposed the removal of alleged "communist-tinged" books from public libraries, and fought rate hikes by public utilities. In addition, he exposed a municipal corruption scheme. Gonzalez's untiring efforts gained him a reputation as a "crusader of the people," championing the ordinary citizen.

Elected to the Texas State Senate in 1956, Gonzalez lived up to his reputation as an opponent of discrimination. He and Senator Abraham Kazen attracted national attention for holding a thirty-six-hour filibuster, the longest one in the history of the Texas Legislature. They succeeded in killing eight out of ten racial segregation bills aimed at circumventing the U.S. Supreme Court's decision in the

Brown v. Board of Education case. In 1958 Gonzalez ran unsuccessfully for governor of Texas. Although an unlikely candidate, he drove across the state of Texas in the old family car, offering an alternative to the race between Governor Daniel and former governor W. Lee O'Daniel. He promised controversial measures, such as a tax on gas pipelines.

Gonzalez developed a strong relationship with John F. Kennedy in the 1950s. He campaigned

for JFK in the 1960 presidential election. As national co-chair of the "Viva Kennedy" organization, Gonzalez worked on behalf of the Kennedy-Johnson ticket in Texas and eleven other states.

During President Kennedy's ill-fated visit to Texas in November 1963, Gonzalez participated in public events in San Antonio, Houston, and Fort Worth with the president. On November 22, 1963, Gonzalez rode in the presidential motorcade in the fifth car behind the president. He went to Parkland Hospital where he stood with Jacqueline Kennedy as she waited to hear the grim news of her husband's assassination. Gonzalez witnessed the First Lady's final kiss and last goodbye to her husband. Gonzalez then flew back to Washington DC on Air Force One with the newly sworn in President Lyndon Johnson, the somber presidential entourage and the body of the slain president. "It's a terrible thing to see a man in the full prime of life, a great human, and see him there dead - shot in the head," Gonzalez told news reporters. "It's hard to believe that something like this could happen to a man you love."